I bring a lot of audio gear home to review. Part of my testing often includes allowing my wife and adult “kids” to listen, and more often than not, while my sons are impressed, my wife is unbothered. When I had her sit down and listen to Fosi Audio’s new i5 planar magnetic headphones and ZH3 desktop DAC/Amp, I was surprised to find that she was blown away!
She said that it sounded like she was listening to live music! That is high praise, coming from someone who is not easily moved by shiny, new gadgets. As I went through my test playlists, I, too, found myself quite impressed by what I was hearing! That said, let’s back up to the beginning of my time with both: the unboxing!
Both products come beautifully packaged and protected inside their boxes. With the Fosi ZH3 desktop DAC/Amp, you get the unit, a 3.5mm-to-6.35mm adapter, a 12V trigger cable, a convertible USB-A or USB-C-to-USB-C cable, a 12V power adapter, an IR remote, and a manual.
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The Fosi i5 planar magnetic headphones come with a 6.35mm adapter, a 1.5m dual 3.5mm cable (plugs into the headphones) with a 4.4mm Balanced termination (plugs into your source), and the manual. No hard case for such pricey headphones because their planar magnetic drivers aren’t meant for traveling.
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Categories |
Fosi Audio ZH3 DAC Headphone Amp |
|---|---|
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Chipset |
XMOS XU316 + AKM4493SEQ + OPA1612 x4 |
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Outputs |
4.4mm Balanced, 6.35mm Single-ended, RCA, XLR |
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Inputs |
Coaxial, Optical, USB-C, RCA |
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Headphone Impedance |
16–300Ω |
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Maximum Sampling Rates |
USB: PCM 32-bit 768 kHz, DSD512 Optical: PCM 24-bit 192 kHz Coaxial: PCM 24-bit 192 kHz |
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Power input |
DC 12V |
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USB Compatible Devices |
Windows 8 or later, macOS X 10.6 or later, Linux |
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Bluetooth Support |
No |
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Color |
Black with Orange volume knob |
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In the box |
External power supply and AC cable, USB C to A, 3.5 mm to 3.5mm aux cable for the trigger, 6.35 mm adapter, Remote control, User manual |
Removing the ZH3 from its box, the first thing to notice is the heft. It’s all aluminum enclosure feels durable and well put together. When powered up with the included 12V power adapter, the lovely LCD display is bright and easily legible.
The volume nob has a satisfying click at each of its 99 steps. On the front, I have access to 6.35mm (¼-inch) and 4.4mm Balanced outputs, more on that in a moment.
The backside of the ZH3 has more inputs and outputs than some pricier DAC/Amps, with three digital and one analog out via an RCA connection. Then there are the outputs on the front that I mentioned, along with RCA and XLR line outs on the back.
You can set the line out for preamp, connecting to another amp with fixed volume, or connect to your desktop, powered speakers/monitors.
The Fosi i5 planar magnetic headphones are swaddled in their packaging like a newborn baby, and are just as beautiful. The large 97mm drivers are encased in a CNC-machined aluminum frame, surrounded by a gorgeous glossy Walnut wood frame.
A “memory alloy” metal frame provides just enough clamping force to keep things in place and comfortable on the head for hours, while the suede headband takes the heft of these 550-gram (~1.2lbs) headphones and distributes it across your head for a soft, breathable, long-wearing experience.
The memory foam-wrapped composite leather earpads further help distribute weight without feeling tight and stay cool during long listening sessions of two to three hours.
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The dual-axis yokes that hold the earcups swivel enough that the i5 should fit comfortably on anyone’s head. We both found the size difference between us amusing. The headband uses a stepless, smooth silicone slider, which was easy to manipulate to seat the suede headband at the proper distance from the earcups.
A powerful pairing!
The i5s are so beautiful and easy to wear that I was eager to start the listening test. One of the most chaotic, frenetic, deeply layered Jazz songs on my test list is Charles Mingus’ “Moanin’,” and as I listen, I’m completely blown away by just how well this pairing handles nuance and instrument placement. I find myself getting lost in all of the little things, two or three layers deep in the mix. Sounds that are often buried by lower-resolution DACs/Amps and headphones.
Next up was System of a Down and “Chop Suey!” The detail retrieval really shines as you listen to the attack and decay of guitar riffs and the resonance of piano key strikes, even at lower volumes. Often, I forget about the attack, or touche, of the piano key strikes on “Chop Suey!” because many headphone/DAC combos I’ve listened to bury them.
On all these heavily instrumental tracks, the i5-ZH3 pairing radiates emotion.
The 808 bass extension on The Roots’ “Do You Want More?!!!??!” is a delight and something I wasn’t expecting at all from a pair of planar magnetic headphones. The deep, resonant bass hits show how dynamic that 97mm driver is, with transients resolving quickly and naturally, rather than overstaying their welcome like a shiftless houseguest.
I’d actually call Fosi’s i5 planar magnetic headphones a bass lover’s pair for how well they reproduce Hip Hop and other bass-heavy genres like Dubstep, D&B, Acid Jazz, and House.
As micro-detailed as the sound reproduction is, one might expect that it may be analytical as well. And, to a degree, you’d be right. Joni Mitchell’s “River (With French Horns)(Blue Sessions)” definitely gets fatiguing on some of the higher notes sung by Mitchell, and struck by the piano accompaniment.
The good news is that the Fosi ZH3 has basic bass and treble gain options to mitigate that if you often listen to music like hers. The ZH3 also has six 32-bit filters built in, but after listening for a while, I had a hard time distinguishing them or their effects on the audio.
Collectively brilliant, AND independently powerful!
Experiencing how each Fosi product behaves on its own, I’m equally as impressed as I am when they’re paired. Connecting the Sennheiser HD660S2 to the Fosi ZH3 is a delight. Though the HD660S2 doesn’t quite have the same low-end impact as the i5, the ZH3 drives it beautifully and is as resolving.
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Categories |
i5 Planar Magnetic Headphones |
|---|---|
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Conectivity |
Wired, 3.5mm |
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Drive units |
Planar Magnetic Drivers |
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Maximum Sound Pressure Level |
>120 dB SPL |
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Frequency Response |
10Hz – 50kHz |
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THD |
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Sensitivity |
98 dB/mW @ 1kHz |
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Nominal Impedance |
28Ω |
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Recommended Power |
≥ 500mW |
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Minimum Recommended Power |
100mW |
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Weight |
550g / ~1lb |
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Color |
Black |
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In the box |
6.35mm Adaptor, 3.5mm Cable with 4.4mm termination, user manual |
The only nitpicky complaint I have is that the audio quality from the Balanced 4.4mm output is audibly better than from the single-ended 6.35mm output. That isn’t too much of a surprise, though, given that the former puts out a whopping 2570mW (2.5 watts) and the latter, 650mW. By the way, that 2.5 watts is more than enough overhead to really push the volume and test for distortion, which I never experienced from either product.
Conversely, the noise floor is black. With both IEMs and over-ear headphones, I hear nothing during quiet sections in songs. No crackle or static. Just darkness. As it should be.
Up next, I connect the i5 to an iFi Go Link Max and FiiO’s excellent M21 DAP. The M21 DAP powers the Fosi i5 headphones with aplomb in high-gain mode via its 4.4mm Balanced Output. The results I got from listening to music were nearly identical to those I had with Fosi’s desktop ZH3 DAC/Amp.
The $70 iFi Go Link MAX performed quite well when using the USB Audio Pro app on a Google Pixel 9 as my music source. It was able to push the Fosi i5’s with relative ease. I only needed to raise the volume to around 70%, unlike when I tried the same setup on an iPhone 16 Pro Max, which required maxing it out. With this setup, things were a bit less detailed.
Ultimately, both the Fosi Audio ZH3 desktop DAC/Amp and i5 planar magnetic headphones are very easy to recommend. With the ZH3, you get excellent input and output options, along with a versatile DAC/Amp that can power just about any headphones you throw at it, as well as your powered speakers. And, at $200, it sounds excellent.
With the i5s, you get a beautifully crafted pair of headphones whose attention to audio detail is just as meticulous as its attention to aesthetics. At $550, they won’t be an impulse buy, but you’ll get a pair of planar magnetic headphones that can go note-for-note with pricier models, without any buyer’s remorse.
